Optical storage discs are commonly known to those skilled in the art. Optical discs may be of the read-only type, where information is recorded during manufacture, which information can only be read by a user. Optical storage discs may also be of a writable type, where information may be stored by a user. Such discs may be a read-once type, indicated as writable (R), but there are also storage discs on which information can be written many times, indicated as rewritable MW). In the case of DVD, a distinction is made between two formats, i.e. DVD-RW and DVD+RW. Since the technology of optical discs in general, the way in which information can be stored in an optical disc, and the way in which optical data can be read from an optical disc are commonly known, it is not necessary here to describe this technology in more detail.
As is commonly known, memory space is divided into blocks, each block having an identification or address, such that a reading apparatus knows which block it is reading.
In the case of RW-type discs, the storage space is physically present in the form of a groove (+RW) or pre-pits (-RW), the blocks are predefined, and the addresses are already allocated and coded in physical hardware features of the storage space. A DVD-ROM reader is not equipped to read this physical coding, and is therefore not capable of reading these addresses. Therefore, in order to facilitate a DVD-ROM reader to read addresses, the addresses are also incorporated in the data to be written.
In the following, the addresses incorporated in physical hardware features of the disc, such as the groove wobble (+RW) or the pre-pits (-RW), will be indicated as hardware addresses, whereas the addresses incorporated in the written data will be indicated as data addresses. Normally, the values of these addresses are identical.
The memory space of a disc is subdivided in lead-in, main data, and lead-out areas. The lead-in area involves a group of blocks at the beginning of the disc, containing information relating to the disc itself. This information includes parameters like disc structure, book type (an indication of the standard used), and header byte, the header byte containing bits indicating area type (lead-in/main data, lead-out/middle data), a bit indicating whether the disc is read-only or not, and a bit indicating the reflectivity of the disc.
The present inventor has found that the playability of a disc depends on the values of said parameters. In this case playability can be defined as the degree to which a disc can be read by a disc drive with little or no errors. The playability is low in a case in which many errors are generated during play-back.
The present invention aims to improve the playability of the storage medium. To this end, the present invention proposes to amend the values of said parameters such that the playability is increased, preferably such that the playability is maximal. In this respect, the present invention is based on the recognition that said parameters are for information purposes only, but do not actually change any setting of a disc drive.
DVD-RW type discs have a further problem in this respect, namely that the storage space portion where these parameters are stored is a pre-embossed area, i.e. an area which is not writeable. Of course, it is not possible to change the values of parameters stored in a non-writeable area.
It is an object of the present invention to provide a solution to this problem.